Notes on Eberlanzia schneideriana and Scopelogena (Ruschieae, Aizoaceae)

Abstract

Eberlanzia is a small genus of eight species, which are found from south-western Namibia to Namaqualand. Eberlanzia schneideriana is characterized by its distinctly velvety leaves and several names were subsumed under it. We show that two of these, Ruschia velutina and R. pillansii, are distinct from E. schneideriana. Of these, R. velutina has the smallest flowers (petals not exceeding 3 mm long; 4–7 mm long in R. pillansii and E. schneideriana). Ruschia pillansii has a low spreading habit, whereas R. velutina and E. schneideriana are erect shrubs. The leaves are characteristically globose, with a distinct apical mucro in R. pillansii, whereas they are trigonous with at least the upper surface flattened in the other two species. The leaves of R. pillansii and E. schneideriana are typically whitish grey under dry conditions, whereas the leaves remain dirty green throughout the year in E. velutina. As a consequence of these differences, we now transfer R. pillansii and R. velutina to Eberlanzia. All three species are threatened by mining and severe overgrazing in the Richtersveld National Park. In a nomenclatural note, we validate the generic name Scopelogena L.Bolus.